No, on the Xiaomi Redmi Note 11S you can use either two Nano SIM cards or one Nano SIM card and one microSD card at the same time, but not all three at the same time. The device supports a dual SIM + microSD slot, but these are combined, which means that the microSD slot takes the place of one of the SIM cards.
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Yes, it works 100% with any SIM card, you can even insert two SIM cards plus a microSD card at the same time. It is ideal for in any country, very good choice.